SBOS775C September   2016  – March 2019 INA302 , INA303

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Typical Application
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Bidirectional Current Sensing
      2. 7.3.2 Out-of-Range Detection
      3. 7.3.3 Alert Outputs
        1. 7.3.3.1 Setting Alert Thresholds
          1. 7.3.3.1.1 Resistor-Controlled Current Limit
            1. 7.3.3.1.1.1 Resistor-Controlled Current Limit: Example
          2. 7.3.3.1.2 Voltage-Source-Controlled Current Limit
        2. 7.3.3.2 Hysteresis
    4. 7.4 Device Functional Modes
      1. 7.4.1 Alert Operating Modes
        1. 7.4.1.1 Transparent Output Mode
        2. 7.4.1.2 Latch Output Mode
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Selecting a Current-Sensing Resistor (RSENSE)
        1. 8.1.1.1 Selecting a Current-Sensing Resistor: Example
      2. 8.1.2 Input Filtering
      3. 8.1.3 Using the INA30x With Common-Mode Transients Greater Than 36 V
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
      3. 8.2.3 Application Curve
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Documentation
    2. 11.2 Related Links
    3. 11.3 Receiving Notification of Documentation Updates
    4. 11.4 Community Resources
    5. 11.5 Trademarks
    6. 11.6 Electrostatic Discharge Caution
    7. 11.7 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

8.1.1 Selecting a Current-Sensing Resistor (RSENSE)

Selecting the value of this current-sensing resistor is based primarily on two factors: the required accuracy of the current measurement and the allowable power dissipation across the current-sensing resistor. Larger voltages developed across this resistor allow for more accurate measurements to be made. Amplifiers have fixed internal errors that are largely dominated by the inherent input offset voltage. When the input signal decreases, these fixed internal amplifier errors become a larger portion of the measurement and increase the uncertainty in the measurement accuracy. When the input signal increases, the measurement uncertainty is reduced because the fixed errors are a smaller percentage of the signal being measured. Therefore, the use of larger-value, current-sensing resistors inherently improves measurement accuracy.

However, a system design trade-off must be evaluated through the use of larger input signals for improving measurement accuracy. Increasing the current-sense resistor value results in an increase in power dissipation across the current-sensing resistor. Increasing the value of the current-shunt resistor increases the differential voltage developed across the resistor when current passes through the component. This increase in voltage across the resistor increases the power that the resistor must be able to dissipate. Decreasing the value of the current-shunt resistor value reduces the power dissipation requirements of the resistor, but increases the measurement errors resulting from the decreased input signal. Selecting the optimal value for the shunt resistor requires factoring both the accuracy requirement for the specific application and the allowable power dissipation of this component.

An increasing number of very low ohmic-value resistors are becoming more widely available with values reaching down to 200 µΩ or lower, with power dissipations of up to 5 W that enable large currents to be accurately monitored with sensing resistors.